﻿318 Scientific Intelligence. 





I. 



II. 



III. 



SiOo 



48-95 



26-11 



4904 



A1 2 3 



25-17 



11-73 



29-01 



Fe 2 3 



9-40 



2-82 



5-56 



MgO 



1-69 



0-67 



0-75 



CuO 



trace. 







0-17 



Na 2 



trace. 







0-50 



K 2 



11-08 



1-88 



11-19 



H 2 



4-31 



3-83 



4-65 



100-60 100-87 



Oxygen Ratios. — Bases with water to silica are as 4:5 nearly. 

 Bases without water to silica are as 2 : 3 approximately. 

 RO + H 2 : R 2 3 : Si0 2 = 5 : 11 : 20. 

 RO : R 3 8 : Si0 2 = 2 : 11-; 20. 



As will be seen the composition of the Texas mica agrees very 

 closely with that of the mica from Hirschburg. It is an evident 

 product of alteration, with some of the characters of a vermicu- 

 lite, and differs in composition from ordinary muscovite only in 

 the absence of the fluorine, and the presence of a somewhat larger 

 amount of magnesia. It appears as if it were an early stage in 

 the alteration of muscovite to vermiculite. 



Mr. Leighton has also made the analysis of a crystalline scale 

 formed in the manufacture of sodium bicarbonate by the ammonia 

 process at Syracuse, N. Y. This scale was deposited on the inner 

 surface of an iron tank in which vapors consisting of ammonia, 

 carbonic dioxide, with small quantities of hydric sulphide are 

 passed through brine holding in solution the chlorides of sodium, 

 magnesium and calcium, with a small amount of calcic sulphate. 

 It has the appearance of a boiler scale from one to two inches 

 thick, with a vitreous luster and a greenish gray color, although 

 sometimes black on the surface. The scale is usually covered 

 with crystal planes which have at first sight the appearance of 

 octahedral forms projecting from the surface, but on closer examin- 

 ation the planes were found to be the termination of prisms 

 (probably monoclinic) extending down into the body of the scale. 

 For the details of the crystallographic work as well as for the 

 methods of analysis we must refer to the original paper. From 

 the means of many determinations the following general result 

 was deduced : 



Found. Theory. Diff. 



NaCl 22-230 2223 



Na 2 C0 3 40-622 40-28 -0-34 



MgC0 3 31-569 31-92 +0'35 



CaC0 3 3559 



FeC0 3 0-080 



H 2 0-630 



C0 2 in excess 0-645 



99-335 



The scale is evidently a triple salt represented by the symbol 

 MgC0 3 . Na 2 C0 3 . NaCl mixed with small amount of impurities, 

 and how closely the analysis corresponds to this theory is shown 



